Recently, an advanced driver assistance system (ADAS) has been greatly drawn attention in vehicle industries. The ADAS is a system which senses dangerous situations occurring while driving a vehicle by using sensors mounted in a vehicle and cope with the dangerous situations to assure driver's safety and provide convenience to the driver.
When driving a vehicle on a protruding narrow road, a driver may not differentiate a road boundary well, such that it is difficult for the driver to drive a vehicle and the risk of accidents is increased.